The purpose of the present proposal is to strengthen and expand the research program on the biology of neoplasia presently carried out in the Department of Pathology of Temple University School of Medicine. The individual research projects include: (1) a study of the factors that control cellular proliferation in mammalian cells; (2) studies on the mechanism of carcinogenesis; (3) the biology of human and experimental melanoma; (4) studies on gene activity in proliferating and non-proliferating cells; (5) melanogenesis during the cell cycle and nucleo-cytoplasmic interchanges;and (6) genetic interactions between tumor and host. The proposed Core Grant would attain these purposes (of expanding and strengthening our research program on the biology of neoplasia) by supporting central facilities for research, to be shared by the investigators. A central theme of this proposal is the application of concepts and techniques of modern cell biology to the study of human neoplastic systems. BIBLIOGRAPHIC REFERENCES: Ide, T., and Baserga, R. Circular dichroism and ethidium bromide binding capacity of chromatin from cells temperature sensitive for the transformed phenotype. Biochem. 15:600-605, 1976. Rossini, M., Lin, J.C., and Baserga, R. Effects of prolonged quiescence on nuclei and chromatin of WI-38 fibroblasts. J.Cell. Physiol. 88: 1-12, 1976.